The present invention relates to a irradiator apparatus and especially to an irradiator apparatus and method for generating ozone within the irradiator which is fed into a fluid being treated in the irradiator.
The importance of chemical and biological contamination of fluids has become a significant factor in the handling and disposal of waste fluids. Chemicals that occur in water following conventional treatment are known to be dangerous to human health. New methods are needed to destroy the chemical structures of toxic materials that occur in water and other fluids. The present method uses a combination of ozone (O.sub.3), oxygen (O.sub.2) and gamma ray (.gamma.) irradiation to destroy the molecular structure of both chemical and biological toxic materials in fluids.
Previous irradiation patents have been primarily directed at destroying biological organisms within fluids. The present concept utilizes the combination of ozone (O.sub.3), oxygen (O.sub.2), and gamma rays (.gamma.) to break up the molecular structure of toxic chemicals and simultaneously destroy biological organisms.
Decomposition of water and other fluids by gamma rays has been known to exist for many years. However, many of the observed results were difficult to explain until the hydrated electron was postulated in the early 1950's. Gamma rays (.gamma.) from both cobalt-60 and cesium-137 have energies so great that they both ionize and excite many liquid molecules along their path, as shown in the following equations: EQU H.sub.2 O+.gamma..fwdarw.H.sub.2 O.sup.+ +e.sup.- s EQU H.sub.2 O+.gamma..fwdarw.H.sub.2 O*
The electron removed from the water molecule has energy of a magnitude such that it also ionizes and excites other fluid molecules. As the electron loses energy, it become subexcitable, then thermal, and finally hydrolyzes.
The positive water or other fluid ions also react with other water or fluid molecules. In water, a hydroxyl free radical is formed as shown in the following equation: EQU H.sub.2 O.sup.+ +H.sub.2 O.fwdarw.H.sub.3 O+OH.sup.o
During this same period of time, the excited water molecules decompose into hydrogen free radicals and hydroxyl free radicals as shown in the following equation: EQU H.sub.2 O*.fwdarw.H.sup.o +OH.sup.o
The three reactive species e-.sub.eg, H.sup.o and OH.sup.o are produced by the irradiation of water and other fluids and result in the decontamination of the fluid. Secondary effects within the fluids also result in the production of hydrogen peroxide, free hydrogen, peroxyle free radicals, and other ions. These secondary species increase the effectiveness of the irradiation to decompose toxic chemicals and biological materials.
Addition of oxygen or a halogen, such as chlorine, to a fluid during irradiation greatly increases the production of hydrated electrons and other reactive ionic species. Positive synergistic effects have been experimentally found to exist when specific materials were added to a fluid just prior to or during irradiation.
In addition to the primary effect of the gamma rays on chemical contaminants and the secondary effects of the hydrated electrons and reactive ions, the gamma rays produce ultraviolet radiation throughout a large volume surrounding the cobalt-60 or cesium-137. When cobalt 60 or cesium-137 is placed in an aqueous environment, Cherenkov radiation is observed. This radiation is produced by electrons that have been knocked off the water molecules and possess a velocity greater than the velocity of light in the aqueous solution. The electrons produce a "bow-wave" of light or radiation that is primarily of the ultraviolet frequency. This "bow-wave" is similar to the "shock-wave" of a super sonic jet plane.
Because of the difference in the particle velocity and the phase velocity of light in the medium, there is no longer complete destructive interference and the electron radiates. This radiation is mostly in the ultraviolet part of the spectrum. However, when one sees Cherenkov radiation, they see only the blue tail of the radiated spectrum. The ultraviolet radiation is thus produced within the medium itself and the problem of minimal depth of penetration from an exterior UV source is eliminated. All of the detoxification and disinfection properties of ultraviolet radiation is obtained throughout the volume of the irradiator.
The present method and apparatus incorporates the combined effects of irradiation and ozonation to destroy both chemical and biological toxic materials. This method also uses the synergistic effects of ozone, oxygen, nitrogen, or air to increase the effectiveness of the irradiation process.
Prior irradiators may be seen in prior U.S. patents including U.S. Pat. No. 3,865,734 for an Irradiator Apparatus which utilizes an irradiator having an irradiation source therein along with means to feed various gases into the irradiator. The gases suggested in this patent are chlorine, ozone and oxygen. In U.S. Pat. No. 4,453,079, improvements include the separation of the irradiator into a series of chambers to take advantage of the fact that irradiation is more effective in a series of irradiation treatments of the fluid. This is useful because radiation sources having a lower level of radiation, such as spent fuel from nuclear plants, can be effectively utilized in the irradiator. This allows the use of what would otherwise be waste nuclear energy from a potential waste product.
The present invention improves on prior art irradiators by using a combination with ozone or oxygen by incorporating an ozone generator into the irradiator housing and using the gamma radiation from the irradiator sources to create the ozone from an air or oxygen pump into the generator and then feeding the ozone rich gas directly into the liquid being treated by the same radiation sources while the liquid is passing through a passageway. Thus, the irradiator is able to act both as the ozone generator and as a fluid treatment irradiator, both using the same radiation source which maybe cobalt-60 or cesium-137 to its own generator and also ionizes other gases being fed through the gamma radiation field therein either while creating the ozone or in a separate operation. The ozone thus created serves as a synergistic agent that greatly increases sterilization and the breakdown of the molecular structure of toxic chemicals.